是的。ordinary dividend 和 qualified dividend 填1040，capital gain 填 schedule D
没有treaty是flat rate 30%，但中美有treaty。
Article 14, paragraph 1: 你在美国雇主处获得的收入在美国缴税。
1. Subject to the provisions of Articles 15, 17, 18, 19 and 20, salaries, wages and other similar remuneration derived by a resident of a Contracting State in respect of an employment shall be taxable only in that Contracting State unless the employment is exercised in the other Contracting State. If the employment is so exercised, such remuneration as is derived therefrom may be taxed in that other Contracting State.
Article 17, paragraph 1: 退休金是在美国雇主获得的也在只在美国缴税。
1. Subject to the provisions of paragraph 2 of Article 18, pensions and other similar remuneration paid to a resident of a Contracting State in consideration of past employment shall be taxable only in that Contracting State.
美国收入税是累计税制，10%是美国的最低income tax bracket。
你根据filing status查一下。married filed jointly 有10%，12%这两档税比较低。
离职就可以做401k-> traditional ira，具体要离职后多久要看401k plan，问问payroll吧。
traditional ira -> roth ira 这一步是你自己向券商发起，速度取决于他们的trustee-to-trustee rollover的转账效率，同在fidelity的话一天就能完成rollover。